An autopsy will be conducted on a 35-year-old Butler County man who died Tuesday — a day after he was found unresponsive in his state prison cell in Fayette County, authorities said.

Raymond M. Seybert, a convicted violent sex offender, was unconscious about 10:20 a.m. Monday when staff at the State Correctional Institution- Fayette found him during a routine security check.

Prison officials reportedly provided emergency first aid before Seybert was taken to Uniontown Hospital.

He eventually was transferred to UPMC Presbyterian in Pittsburgh, where he was pronounced dead at 5:36 a.m. Tuesday, according to the Allegheny County Medical Examiner’s Office.

An autopsy is planned today or Thursday to determine a cause of death, authorities said.

State police are investigating the case. No other details were available this morning.

Seybert had been at SCI-Fayette since June 2004 while serving a 10- to 32-year sentence for sexually assaulting a 14-year-old Penn Township girl.

A Butler County jury convicted him in the 2001 assault.

Only months before the that incident, Seybert was released from prison after serving time for sexually assaulting a 9-year-old Butler girl the summer before, court records showed.

Seybert was deemed a sexually violent predator under the state’s Megan’s Law after his earlier sexual assault conviction.

Additionally, he had a juvenile record involving sex crimes, according to testimony at his sentencing hearing in 2002. At 16, he was convicted of indecent assault involving four girls between 5½ and 10 years old.

In 2003, while an inmate at the Butler County Prison, Seybert was caught with a shank that he crafted from metal scraps, a paper clip, pen and coat hangar, court documents said.

He subsequently pleaded guilty to a charge of possessing a weapon or implement of escape. The conviction earned him an additional 1 to 2 years in state prison.